Agricultural practices to improve nitrogen use efficiency through the use of arbuscular mycorrhizae:basic and agronomic aspects

Nitrogen cycling in agroecosystems is heavily dependent upon arbuscular mycorrhizal fungi (AMF) present in the soil microbiome. These fungi develop obligate symbioses with various host plant species, thus increasing their ability to acquire nutrients. However, AMF are particularly sensitive to physical, chemical and biological disturbances caused by human actions that limit their establishment. For a more sustainable agriculture, it will be necessary to further investigate which agricultural practices could be favorable to maximize the benefits of AMF to improve crop nitrogen use efficiency (NUE), thus reducing nitrogen (N) fertilizer usage. Direct seeding, mulch-based cropping systems prevent soil mycelium disruption and increase AMF propagule abundance. Such cropping systems lead to more efficient root colonization by AMF and thus a better establishment of the plant/fungal symbiosis. In addition, the use of continuous cover cropping systems can also enhance the formation of more efficient interconnected hyphal networks between mycorrhizae colonized plants. Taking into account both fundamental and agronomic aspects of mineral nutrition by plant/AMF symbioses, we have critically described, how improving fungal colonization through the reduction of soil perturbation and maintenance of an ecological balance could be helpful for increasing crop NUE

In winter wheat (Triticum aestivum L.), no-till improves photosynthetic nitrogen and water use efficiency

International audienc

In winter wheat (Triticum aestivum L.), no-till improves photosynthetic nitrogen and water use efficiency

International audienc

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

In this review, we present the recent developments and future prospects of improving nitrogen use efficiency (NUE) in crops using various complementary approaches. These include conventional breeding and molecular genetics, in addition to alternative farming techniques based on no-till continuous cover cropping cultures and/or organic nitrogen (N) nutrition. Whatever the mode of N fertilization, an increased knowledge of the mechanisms controlling plant N economy is essential for improving NUE and for reducing excessive input of fertilizers, while maintaining an acceptable yield and sufficient profit margin for the farmers. Using plants grown under agronomic conditions, with different tillage conditions, in pure or associated cultures, at low and high N mineral fertilizer input, or using organic fertilization, it is now possible to develop further whole plant agronomic and physiological studies. These can be combined with gene, protein and metabolite profiling to build up a comprehensive picture depicting the different steps of N uptake, assimilation and recycling to produce either biomass in vegetative organs or proteins in storage organs. We provide a critical overview as to how our understanding of the agro-ecophysiological, physiological and molecular controls of N assimilation in crops, under varying environmental conditions, has been improved. We have used combined approaches, based on agronomic studies, whole plant physiology, quantitative genetics, forward and reverse genetics and the emerging systems biology. Long-term sustainability may require a gradual transition from synthetic N inputs to legume-based crop rotation, including continuous cover cropping systems, where these may be possible in certain areas of the world, depending on climatic conditions. Current knowledge and prospects for future agronomic development and application for breeding crops adapted to lower mineral fertilizer input and to alternative farming techniques are explored, whilst taking into account the constraints of both the current world economic situation and the environment. agriculture; cover cropping; conservation tillage; fertilizers; genetics; nitrogen; green manure; agro-biodiversity, sustainability

In winter wheat (Triticum aestivum L.), no-till improves photosynthetic nitrogen and water use efficiency

International audienc

Identification of Phenotypic and Physiological Markers of Salt Stress Tolerance in Durum Wheat (Triticum Durum Desf.) through Integrated Analyses

International audienc

Investigating the combined effect of tillage, nitrogen fertilization and cover crops on nitrogen use efficiency in winter wheat

A field study was conducted in northern France over two consecutive years to evaluate the combined effect of conventional tillage (CT) vs no till (NT) with or without cover crops (cc) and nitrogen (N) fertilization on various agronomic traits related to N use efficiency in winter wheat. Five years after conversion of CT to NT, significant increases in N use efficiency, N utilization efficiency, N agronomic efficiency, N partial factor productivity, N apparent recovery fraction and N remobilization were observed under three N fertilization regimes (0, 161, 215 kg ha(-1)). It was also observed that grain yield and grain N content were similar under CT and NT. The N nutrition index was higher under NT at the three rates of N fertilization. Moreover, N use efficiency related traits were increased in the presence of cc both under NT and CT. Thus, agronomic practices based on continuous NT in the presence of cc, appear to be promising strategies to increase N use efficiency in wheat, while reducing both the use and the loss of N-based fertilizers

Conversion to no-till improves maize nitrogen use efficiency in a continuous cover cropping system

A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize

Informer avec Internet

L’information d’actualité a toujours connu des contours imprécis, malgré l’unité apparente des termes génériques comme « le » journal, ou « la » radio ; ses objets ne cessent de circuler et de se modifier sous des formes qu’on doit désormais désigner au pluriel : « les » réseaux sociaux, par exemple. L’information, a sans doute aussi, toujours été caractérisée par sa mobilité, une intertextualité constitutive puisqu’elle est d’abord faite d’un assemblage de discours prélevés auprès des acteurs sociaux, et une dispersion des formats, des modèles, et des dispositifs. Cependant, le développement puis l’omniprésence d’Internet reconfigurent en profondeur le paysage médiatique et imposent de réfléchir aux définitions, et aux catégories sur lesquelles reposent nos connaissances. C’est l’objectif de ce livre que d’interroger la diversité des formes contemporaines de l’information d’actualité : l’ensemble des recherches réunies ici contribuent d’abord à une nouvelle compréhension de la notion d’actualité par des choix méthodologiques variés (quantitatifs et qualitatifs) et des approches disciplinaires nombreuses dont le croisement est devenu indispensable (sciences de l’information-communication, bien sûr, mais aussi sciences du langage, ou droit). Les résultats tout comme les questions soulevées par les travaux publiés rendent compte de la richesse des modes d’existence de l’information et posent des jalons pour l’analyse de ses évolutions et de ses métamorphoses

Control of the Synthesis and Subcellular Targeting of the Two GDH Genes Products in Leaves and Stems of Nicotiana plumbaginifolia and Arabidopsis thaliana

doi:10.1093/pcp/pcj008, available online at www.pcp.oupjournals.or